CODEWITHSUNDEEP
javascriptregexsplit
Haider Ali
Haider Ali

Reputation: 964

Split string at every nth linebreak using javascript

I'm looking for a solution to split a string at every nth linebreak. Lets say i have one string that has six lines

"One\nTwo\nThree\nFour\nFive\nSix\n"

So splitting at 3rd line break would give me something like

"One\nTwo\nThree\n" and "Four\nFive\nSix\n"

I've found solutions to do it at nth character, but i can't be definite of at what character length the nth break would occur. I hope my question is clear. Thanks.

Upvotes: 8

Views: 2672

Answers (2)

Casimir et Hippolyte
Casimir et Hippolyte

Reputation: 89639

Instead of using the String.prototype.split, it's easier to use the String.prototype.match method:

"One\nTwo\nThree\nFour\nFive\nSix\n".match(/(?=[\s\S])(?:.*\n?){1,3}/g);

demo

pattern details:

(?=[\s\S]) # ensure there's at least one character (avoid a last empty match)

(?:.*\n?)  # a line (note that the newline is optional to allow the last line)

{1,3} # greedy quantifier between 1 and 3
      # (useful if the number of lines isn't a multiple of 3)

Other way with Array.prototype.reduce:

"One\nTwo\nThree\nFour\nFive\nSix\n".split(/^/m).reduce((a, c, i) => {
    i%3  ?  a[a.length - 1] += c  :  a.push(c);
    return a;
}, []);

Upvotes: 4

Jan
Jan

Reputation: 43199

Straight-forward:

(?:.+\n?){3}

See a demo on regex101.com.

Broken down, this says:

(?:  # open non-capturing group
.+   # the whole line
\n?  # a newline character, eventually but greedy
){3} # repeat the group three times

Upvotes: 2

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